GPT-5 Pro vs GPT-5.3 Chat
Compare GPT-5 Pro and GPT-5.3 Chat, both from OpenAI, context windows of 400K vs 128K, tested across 41 shared challenges.
Our Verdict
GPT-5 Pro
GPT-5.3 ChatRunner-up
No community votes yet. On paper, GPT-5 Pro has the edge — bigger model tier, bigger context window.
GPT-5.3 Chat is 8.6x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
GPT-5 Pro
Input
$15.00
Output
$120.00
GPT-5.3 Chat
Input
$1.75
8.6× cheaper
Output
$14.00
8.6× cheaper
GPT-5.3 Chat is cheaper on both — 8.6× input, 8.6× output
Writing DNA
Style Comparison
Similarity
50%
GPT-5.3 Chat uses 171.1x more bold
GPT-5 Pro
GPT-5.3 Chat
65%Vocabulary59%
15wSentence Length26w
0.32Hedging0.84
0.0Bold1.7
2.9Lists6.6
0.00Emoji0.00
0.00Headings0.00
0.01Transitions0.25
Based on 11 + 23 text responses
Research
What we learned reading every model
FAQ
Common questions
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